Best Target Speed for 16" Barrel AR-15 .223

[HorizontalMike]

I tried searching, however, have not found useful information thus far. While understanding that there are numerous variables with powders & bullets, my question(s) is/are:

For the 16in barrel .223 S&W AR-15:

• What fps-speed (2,800-3,100fps) have you found to be most accurate for this length S&W barrel?
• What bullets from ~50-55g were used to determine the above "best accuracy"?
• What understanding of barrel "harmonics" do you have, or would recommend the OP to research?
• AFTER documenting the above, what advice would/could you offer from your OWN experience?

FWIW, I am trying to minimize wasting rounds (during the pandemic) trying to find out a decent (though not perfect) load for my Sport II. Following the Sierra Manual(v.5) for #1400 .224" 53gr. HP MatchKings, I am planning to use reloads of 24.0gr on the low end and 24.9gr. on the high end, trying to avoid both extreme ends of the Sierra Manual Envelope so to say (Min=23.1gr, Max=25.2gr).

If I really had to sum this all up, what end of the speed spectrum tends to be the most accurate for 16" S&W Sport II Barrels?

 

[rockquarry]

Just a suggestion... Whether this will still work well nowadays, I don't know. I used to call Sierra with questions and it saved me a lot of work. The guy I always dealt with, Carroll Pilant, retired several years ago, but it might still be worth a call. Seems there would be others at Sierra that can answer any of your questions, especially since your using their bullet. Good luck-

 

[HorizontalMike]

Just a suggestion... Whether this will still work well nowadays, I don't know. I used to call Sierra with questions and it saved me a lot of work. The guy I always dealt with, Carroll Pilant, retired several years ago, but it might still be worth a call. Seems there would be others at Sierra that can answer any of your questions, especially since your using their bullet. Good luck-

Hey thanks for the suggestion... I will indeed do as you suggest, in time... FWIW, I do have safe parameters via "Sierra Bullets" v.5 Manual, what I am truly asking is WHO has personal experience with this load in THIS weapon?... Not looking for perceptions/interpretations.

I have absolutely NO problems with who offer suggestions, however, I am looking for results from those who have actually measured same. BTW, I am not trying to be their "test bunny's" ... as an experiment.

 

[Ivan the Butcher]

When loading 223's, I found a load I liked. That load served well with several semi-autos and bolt guns. For holes in paper I recommend 26.0 of WW748, CCI Sm Rifle Mag primmer, and Winchester 55gr FMJ/BT. COAL was set to the cannular. In my 20" AR (Bushmaster, 1996) with a 20x scope, 5 shot groups average 3/8" @ 100 yards. Plenty accurate for "Run & Gun!"

I know all bullets are hard to find right now, BUT, I found Winchester FMJ's are better by a large margin over Hornady!(Didn't try others) The CCI Sm Rifle Mag primer can be substituted with Rem 7 1/2 (but they usually cost more.)

The above load is an accuracy load from Lyman #45. If you use standard primers, you will probably need to up the powder by 4 tenths.

I loaded 20,000 of these in 1984/5 and still have around 2000, They still shoot good. 2000 of them went to the second son's Stag LH M-4, and performed to his USMC standards!

I hope this info helps.

Ivan

 

[HorizontalMike]

Thanks guys. What I forgot to mention is that I already have onhand:

• Just a bit less than 16lb of H322
• Have 3,500 53gr Sierra Match Kings
• ~4,950 Rem #7-1/2 primers
• 2K of new brass and ~1,500 loaded OEM rounds all re-loadable
• I got the powder/charge range for the above bullets and powder, from the Sierra v.5 manual p.217.

Sorry about not specifying this before...
So, I am rather restricted/locked into using H322 and #1400 53gr. Match King bullets while this pandemic drags on... BTW, Sierra used a 20 inch test barrel with a 1:7 twist. My S&W Sport has a 1:9 twist 16in. barrel.

That said, I am STILL very interested in hearing about the best FPS out of the .223 16 inch barrels. Regardless of powders, but bullets close to my 53gr (I'll take any information on 50-55gr). And any info on barrel harmonics too!

Thanks in advance!

 

[Ivan the Butcher]

H322 is a great powder! It was designed to be equal to Thunderbird T-32, THE Powder for shoot Bench Rest with PPC and BR cases!

My bolt gun shoot a H322 load into tiny tiny groups! But is a few tenths over max for AR's

My suggestion would be; go to the Sierra and look at the load at the bottom of the section for that bullet, the accuracy load. Find the H322 line and go to that accuracy velocity and use that charge.

I don't believe that bullet has a cannelure, be sure to use a pretty stout taper crimp! COAL on all 223 AR's is 2.25" Max.

Ivan

 

[jjfitch]

Asking about accuracy loads is like asking "How long is a piece of string?"

Your barrel will determine what it likes. My load data is similar to one listed above in one 16" AR but not the best in another 16" AR and different than my 20" load data.

Even finding an accurate load and then change barrel tension or recoil device! Barrel harmonics changes affect accuracy as much as load data!

Smiles,

 

[Engineer1911]

With 16 # of powder, 3,500 bullets, and 4,949 primers, plus words of wisdom from Sierra, you should be able to start reloading. Until you load the first 5 rounds and shoot them, your experience base is zero.

Ypu will never run low on supplies if you don't pull the trigger. It is a 223 rifle, not an atomic bomb: close still counts.

 

[mtgianni]

A very humble man whom I considered a genius was discussing barrel harmonics as I listened in. In general barrels are happiest in harmonics of 800 fps multiples, ie, 800, 1600, 2400 and 3200 fps. Secondary nodes occur at the half points, ie, 1200, 2000, 2400 and 2800. That allows you to go for 2800 or 3200 based solely on harmonics.

 

[Johnrh]

Never worried about barrel harmonics with an AR. Benchrest rifles yes, AR's no. I've shot matches against some very good shooters and never once was barrel harmonics mentioned. Powder, load and bullet and test, for the 600 line it was about bullet jump as they are too long for a magazine.

 

[Scharfschuetzer]

As noted above, your AR will tell you what it likes after shooting groups starting on the low end an working up to a max load with your components.

Is your barrel free floating or is it secured at the end of the handguard as most 16" ARs are? Any discussion of barrel harmonics will need to start with this.

What is your rifling twist? a 1 in 14" is actually the best for your 53 grain SMKs, although a 1 in 12" twist is very good with this bullet also. I've shot a lot of prairie dogs with the SMK 52 and 53grain MK bullets out of a 1 in 14" and 1 in 12" twist rifles. Faster twists can be as accurate, but generally over stabilize these light bullets and accentuate any concentricity issues a bullet might have, thus opening groups up a bit.

Your actual chamber's throat (lead) may also have something to do with the accuracy you obtain with the light SMKs. The GI chamber's throat v. a .223 chamber's throat v. a Wilde chamber with its compromise throat. A long bullet jump can degrade accuracy a bit, but can lower chamber pressure.

All the above can impact accuracy, both positively or negatively. So what's the answer? Just work up your loads till you find one that meets your accuracy and velocity goals.

Let us know what your results are.

 

[rockquarry]

As noted above, your AR will tell you what it likes after shooting groups starting on the low end an working up to a max load with your components.

Is your barrel free floating or is it secured at the end of the handguard as most 16" ARs are? Any discussion of barrel harmonics will need to start with this.

What is your rifling twist? a 1 in 14" is actually the best for your 53 grain SMKs, although a 1 in 12" twist is very good with this bullet also. I've shot a lot of prairie dogs with the SMK 52 and 53grain MK bullets out of a 1 in 14" and 1 in 12" twist rifles. Faster twists can be as accurate, but generally over stabilize these light bullets and accentuate any concentricity issues a bullet might have, thus opening groups up a bit.

Your actual chamber's throat (lead) may also have something to do with the accuracy you obtain with the light SMKs. The GI chamber's throat v. a .223 chamber's throat v. a Wilde chamber with its compromise throat. A long bullet jump can degrade accuracy a bit, but can lower chamber pressure.

All the above can impact accuracy, both positively or negatively. So what's the answer? Just work up your loads till you find one that meets your accuracy and velocity goals.

Let us know what your results are.

It seems twist rates are often very generalized when it comes to ARs. Some 1 in 7" to 1 in 9" twist guns will shoot the light 52-55 grain bullets as well as the slower twist bores will, so "over stabilizing" a bullet is seldom a concern with .224" bullets of reasonable weight. I don't know about bullets as light as 40 or 45 grains.

Under stabilizing them is different; they won't shoot well.

 

[WR Moore]

Without an idea of what accuracy you might be trying to get it's a bit difficult. I mean ARs aren't bench rest rifles.

I've seen very good accuracy slightly over 2900 f/s out of a 16 in barrel. Exact bullet doesn't seem to matter all that much, the 55 gr BK has done well on groundhogs.

A big problem with the 1-7 twist is bullets coming apart on their way down range. Usually happens with really fragile varmint bullets but did see it with some soft points (don't recall brand). 1-9 was found in NRA testing to provide better accuracy.

 

[HorizontalMike]

My suggestion would be; go to the Sierra and look at the load at the bottom of the section for that bullet, the accuracy load. Find the H322 line and go to that accuracy velocity and use that charge.
I don't believe that bullet has a cannelure, be sure to use a pretty stout taper crimp! COAL on all 223 AR's is 2.25" Max.
Ivan

Ivan, that sounds like a plan! Accuracy Load = VV N133 @ 23.5gr = 2,900fps

My preloaded (30each) mags have 24.0gr and 24.9gr.
At 23.8gr Sierra says ~2900fps (20in barrel), so... my 24.00gr load may be very close to that 2,900fps. THOSE should be just fine. What I am wondering about is the 24.9gr work-up load. Other than Sierra, all other sources say 23.5gr MAX.

AND YES, Engineer1911 is quite correct that I have zero experience, not having fired any of these loads once at this point. I have valued his advice for quite some time now, and agree. FWIW, I am just a scaredy-cat 68yr old man with prior experience with +55 broken bones, mostly ribs, back, and know all too well about being on a ventilator for over two weeks, less than 5yr ago.
Not wishing to repeat that experience, I am keeping as low a profile as I can. I have even curtailed my Harley riding this year, for the same reason...
Last I checked, Texas ranked number two, behind CA, in having most covid-19 cases...

Accounting for the length of the barrel 20in vs 16in and roughly 100fps loss, load data suggests 24.5gr for 20in barrel at 3,000fps. So, if I figure this reasonably correctly, my 16in barrel will push ~2,900fps at 24.5gr... smack dang between the two test loads I have waiting to shoot... Sounds safe enough to blindly load a batch. Not looking for BR competition, just reliable and reasonably accurate.

All said and done, I have just re-furbed my shot-up HG range target at home, and dug out the lead. At least I can get back to that with gusto, not overly paranoid with a mask, just ear plugs! Trying to keep safe AND keep shooting.

 

[AJ]

Do you have anything that shoots well in your rifle now? For me it is Federal American Eagle Varmint & Predator which is a 50 Grain JHP at 3325 FPS. This will shoot three shots touching in a 4.5 inch bull at 100 yards off the bench. To get reloads to shoot the same grouping a friend and I did some testing (read lots of shooting). We used Sierra 52 grain HPBT's and several different powders. Would pick a loading that approximated the Federal loading (used Quick Load on the computer to get a rough idea of what we wanted). Then we would load groups of rounds (15) that were a couple of 1/10's above and below the recommended. Tossed out the ones that did not group well and worked with the ones that did. Ended up with 25.4 grains of H335 with the 52 grain Sierra HPBT that duplicates the same accuracy in my rifle.

 

[Nevada Ed]

In all of my rifles from .22 up to .30 Cal...........
the larger size bullets always did better at the medium or slower speeds for my accuracy target loads, with stock barrel twist.

None were 16-18" in barrel length, so your powders need to be looked up and decided on for your fps area.

Have fun.

 

[WR Moore]

About "all other sources" max loads. My 2012 Hornaday and an older Sierra manual list H322 max loads with that bullet at 25 grains and a wee bit more.

Back when I was shooting long range I worked up loads in .308, I was under max by the then current Sierra manual. When a new manual came out, I browsed a copy to see if there were any new developments and found the load I'd been using was now way over the line. I promptly called Sierra and they explained the difference was due to a different rifle.

To quote the tech:"If you don't have the velocity, you don't have the pressure." While not entirely true, it's a pretty decent rule of thumb if there's no other factors.

 

[Engineer1911]

Did you pull the trigger on your reloads?

 

[fredj338]

There is no optimal load or vel when it comes to accuracy in rifles. Its all about the bullet. Your bbl will tell you what itblikes at what Vel. If you are just punching holes at 100y, anything will do that shoots submoa.
Imo, your reloading technique is out if whack. You work up loads in any rifle for accuracy, not just stab a point in a book & load 100s. Pick a bullet & powder. Start at midrange & load 3rds then 3 more 2/10gr higher & continue until you are about 5% from max. Shoot them in order for groups off a good bench. Your rifle will have a pref. The best 3 shot group gets loaded in 3-5rd batches for final testing, preferably at 100, 200 & 300.

 

[BLUEDOT37]

I too just got a Sport II & started loading for it too.

As already mentioned, I think you should load up a work-up string from your starting load, in .5gr increments, & see how the AR functions with them (& get it loosened up) & how they group.

Since these are 5.56 NATO chambered, & thus have the longer leades/freebore, I don't see much sense in wasting time/ammo trying to see if COAL" makes a noticeable difference in accuracy. Additionally, my bullets have cannelures to seat to.

Right now I'm limited to shooting at 25yds max anyway & surely don't anticipate shooting beyond 100yds at this time, plus I'm just using a SIG Romeo 5XDR red dot.

I had three powders to play with: RE 10x, Benchmark, & BLC-2 along with a bunch of 55gr, & some 62gr bullets, both FMJ-BT w/cannelure.

Went with a near max load of the RE 10x for the 55gr bullets & the BLC-2 for the 62gr FMJ & 64gr JSP bullets.

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